The function of the Epstein-Barr virus nuclear antigen (EBNA) 3 genes will be analyzed. This approach will be a three-fold effort. First, genetic analysis of these genes will be preformed by generating a series of deletional and insertional mutants and assessing the effect of these mutations on the ability of the recombinant viruses to transform primary B lymphocytes as wild-type EBV does. Second, a search for cellular proteins that interact with the EBNA 3 proteins will be undertaken by using the yeast two-hybrid system and fusion-protein pull-down experiments. Once these proteins are identified, the function significance of their interactions with the EBNA 3 proteins will be analyzed by altering the ability of these interactions to occur in the cell and determining the effect on transformation of primary B lymphocytes. Finally, because the EBNA 3 proteins are nuclear proteins and have been shown to interact with RBJk, a cellular DNA binding protein, the induction of cellular genes by these proteins will be studied. To do this, cell lines that express each of the EBNA 3 protein independently will be compared to EBV infected cell lines and noninfected cell lines by differential display analysis. The cDNA's for the cellular genes induced by the EBNA 3 proteins will be cloned and analyzed.